Bale stacker

ABSTRACT

Apparatus for for stacking papermaking pulp bales is disclosed, comprising two sets of lifting forks, which are directed towards each other for lifting bales, and a conveyor for inserting a new bale beneath the lifted bales. The lifting forks are horizontally movable between an advanced active lifting position and an inactive retracted position and have forward portions with a continuously decreasing thickness. The drive means for the lifting forks comprise a motor and a freewheel clutch for lifting and lowering the lifting forks, so that the lowering movement for both sets of lifting forks is automatically and individually adapted to their pulling-out movement when they rest on the underlying bale, although the speed of the drive motors which operate in a synchronized manner need not be controlled.

FIELD OF THE INVENTION

The present invention relates to a bale stacker for stacking pulp bales,comprising lifting forks driven by a drive means for lifting bales whichare already stacked, and a conveying means for inserting a new balebeneath the lifted bales, which lifting forks are movable horizontallybetween advanced active lifting position and inactive retractedposition.

BACKGROUND OF THE INVENTION

Papermaking pulp bales are usually held together by being tied withsteel wire. A number of such bales are then stacked in a usual mannerand tied around with steel wire to form an assembled bale stack.Previous stackers were utilized which placed a new bale above an alreadystacked bale. At present, stackers are used which lift the alreadystacked bales and insert a new bale beneath the already lifted bales.The lifted bale stack is then lowered onto the lowermost bale, and thelifting forks are pulled out so that the stack falls down onto thelowermost bale with a loud sound. Papermaking pulp bales are often notentirely rectangular, and this sound is especially loud when a balethuds down onto a bale with an inclined upper surface. One or severalbales can thus fall off the stack. International Applicaiton No.WO-00/09430 shows examples of known bale stackers.

One object of the present invention is to provide, in a simple andcost-effective way, a rapid and efficient bale stacker, which isrelatively quiet and operates with greater safety than previously knownbale stackers.

SUMMARY OF THE INVENTION

This and other objects of the present invention have now been realizedby the discovery of apparatus for stacking a plurality of balescomprising a plurality of lifting forks for lifting the plurality ofbales at a first location, a conveyor for transporting the plurality ofbales to the first location, whereby when one of the plurality of baleshas been lifted from the first location another of the plurality ofbales can be transported to the first location beneath the one of theplurality of bales, the plurality of lifting forks being horizontallymovable between a first advanced lifting position and a second inactiveretracted position, the plurality of lifting forks including an endportion of continuously decreasing thickness, and driving means fordriving the plurality of lifting forks, the driving means comprising amotor and a free wheel clutch for lifting and lowering the plurality oflifting forks.

In accordance with one embodiment of the apparatus of the presentinvention, the apparatus includes a traveling crab for carrying theplurality of lifting forks, vertical guide means for guiding thetraveling crab in a vertical direction, a chain for driving thetraveling crab, and a driving sprocket, the chain running over thedriving sprocket, wherein the free wheel clutch is assembled with thedriving sprocket. In accordance with another embodiment of the apparatusof the present invention, the plurality of lifting forks comprises afirst plurality of lifting forks and including a second plurality oflifting forks, each of the first and second plurality of lifting forksbeing directed towards the conveyor for jointly lifting the plurality ofbales, the conveyor disposed to transport the plurality of bales in adirection transverse to the plurality of lifting forks.

In accordance with another embodiment of the apparatus of the presentinvention, the apparatus includes a first traveling crab for carryingthe first plurality of lifting forks and a second traveling crab forcarrying the second plurality of lifting forks, first vertical guidemeans for guiding the first traveling crab in a vertical direction,second vertical guide means for guiding the second traveling crab in avertical direction, a first chain for driving the first traveling crab,a second chain for driving the second traveling crab, a first drivingsprocket, the first chain running over the first driving sprocket, and asecond driving sprocket, the second chain running over the seconddriving sprocket, wherein the free wheel clutch comprises a first freewheel clutch assembled with the first driving sprocket and a second freewheel clutch assembled with the second driving sprocket. Preferably, theapparatus includes a first motor for driving the first chain and asecond motor for driving the second chain, the first and second motorsbeing synchronous.

The objects of the present invention are thus achieved in principle bythe drive means for the lifting forks comprising a motor and a freewheelclutch for lifting and lowering the lifting forks.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be more fully appreciated with reference tothe following detailed description which, in turn, refers to thefigures, in which:

FIG. 1 is a side, elevational view of a bale stacker in one embodimentof the present invention, as seen in the direction indicated by thearrows 1—1 in FIG. 2;

FIG. 2 is a top, elevational view of the bale stacker shown in FIG. 1;and

FIG. 3 is a rear, elevational view of the bale stacker shown in FIG. 1,taken as indicated by the arrows 3—3 thereon.

DETAILED DESCRIPTION

The bale stacker shown in the Figures has a rigid steel frame 11fastened with bolts onto the floor. In the frame a conveyor, 12,13, islocated which from an external conveyor (not shown) feeds bales 14 oneby one (only one bale is shown, and only in FIG. 1) to the stackingposition in the bale stacker, and then feeds a bale stack out to asecond conveyor (not shown). It is important to position a baleaccurately, and the bale stacker has several positioning means, whichare not shown and described, because they belong to known andconventional art.

On each side of the conveyor, 12,13, a lifting means, 15,16, is located,both of which have a number (which is three in the embodiment shown) oflifting forks, 17,18 and 19, and 20,21 and 22, respectively, which areslightly lower than the conveyors at the lower end positions. The outerportions 23 of the lifting forks have a continuously decreasingthickness, as shown in FIG. 1. The lifting forks, for example, can havea thickness of about 30 mm, and the chamfered front portion can bechamfered to a thickness of from about 5 mm to 10 mm at the point. Theentire portion of the lifting forks which is inserted beneath a balesuitably can be chamfered.

The lifting means, 15 and 16, thus are the drive means for lifting andlowering the lifting forks. They are identical, and only the liftingmeans 15 shall be described in detail with reference to FIG. 3. It has atravelling crab 30 (the lifting means 16 has a corresponding travellingcrab 29), which runs in two vertical guides, 31 and 32. It is drivenalong the guides by two endless chains, 33 and 34, which run over twodriven upper sprockets, 35 and 36, and two lower free-rolling sprockets,47 and 48. A motor 37 drives synchronously the two sprockets, 35 and 36,over a gear box 38. The sprockets, 35 and 36, have built-in freewheelclutches of a conventional kind, and the freewheel clutches aretherefore not shown. A power means in the form of a cylinder 42 iscoupled to the three lifting forks, 17,18 and 19, coupled together, sothat they are movable horizontally in their longitudinal directionbetween an advanced active lifting position and a retracted inactiveposition. The lifting forks are guided in guides, 43,44 and 45, on thetravelling crab 30 and are arranged so that they follow along in thevertical movements of the travelling crab 30. The crab has an outwardmovable positioning means 46, which is controlled by a power means (notshown), for example a cylinder.

A bale stacking cycle will now be described. An external conveyor (notshown) moves a bale in to the conveyor, 12 and 13, which moves the baleto a hinged stop means (not shown), which places the bale in correctposition in the longitudinal direction of the conveyor. Thereafter thebale is positioned in correct position in the direction transverse tothe conveyor by guide pads 46 of the travelling crabs. The liftingforks, 17–19 and 20–22, of the two travelling crabs, 29 and 30, are inan advanced position, but are in their lower end positions, in whichthey are on a lower level than the conveyor and, therefore, do notdisturb the bale 14. During the positioning of the bale the travellingcrabs, 29 and 30, are moved synchronously upward so that theiroppositely directed lifting forks will lift the bale. The bale havingbeen lifted, a new bale is moved in beneath the lifted bale and ispositioned in the longitudinal and transverse directions by positioningmeans (not shown). The travelling crabs are now moved synchronouslydownward, and when they arrive at the lower bale, their lifting forksare pulled outward by their respective cylinders so that they releasethe bale, and the travelling crabs can continue to be moved downward totheir lower end positions. There, the lifting forks are moved in to eachother again, and then the travelling crabs are again moved up, and thelifting forks this time lift the two bales so that a third bale can beinserted beneath them, and they can be lowered down upon this bale, sothat the bale stack now comprises three bales. In this way the desirednumber of bales can be stacked, and the conveyor, 12 and 13, can thenmove the bale stack to an external conveyor, which moves the bale stackto a station to be tied around.

Due to the chamfering of the forks, a lifted bale can land softly on thelower bale, provided that the vertical movement of the fork issynchronous with its pulling-out movement. Owing to the fact that thetravelling crabs, and thereby the lifting forks, are driven by means offreewheel clutches, it is ensured that this movement will besynchronous, without requiring a complicated control system, because thesynchronized motors can operate at constant speed, and the verticalspeed of the lifting forks is therefore automatically adapted when thelifting forks rest on the lower bale. The two pairs of lifting forks arein this way adapted individually to the upper surface of the bale, andboth pairs are pulled out resting on the upper surface of the lower baleeven when said upper surface is inclined. As soon as the lifting forksno longer rest on the bale, the travelling crabs, and thereby thelifting forks, resume their downward speed, as determined by the motors.The lifting motors are permanently synchronized, and the verticalmovement of the lifting forks is synchronized until a freewheel isactivated during the lowering movement. When both pairs of lifting forksare lowered to their lower end positions, they are again synchronizedbefore the next lifting movement.

The invention is described with reference to the stacking of bales withpapermaking pulp, but can, of course, be used also for the stacking ofother types of bales.

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It is therefore to be understood that numerousmodifications may be made to the illustrative embodiments and that otherarrangements may be devised without departing from the spirit and scopeof the present invention as defined by the appended claims.

1. Apparatus for stacking a plurality of bales comprising a plurality oflifting forks for lifting said plurality of bales at a first location, aconveyor for transporting said plurality of bales to said firstlocation, whereby when one of said plurality of bales has been liftedfrom said first location another of said plurality of bales can betransported to said first location beneath said one of said plurality ofbales, said plurality of lifting forks being horizontally movablebetween a first advanced lifting position and a second inactiveretracted position, said plurality of lifting forks including an endportion of continuously decreasing thickness, and driving means fordriving said plurality of lifting forks, said driving means comprising amotor and a free wheel clutch for lifting and lowering said plurality oflifting forks.
 2. The apparatus of claim 1 including a traveling crabfor carrying said plurality of lifting forks, vertical guide means forguiding said traveling crab in a vertical direction, a chain for drivingsaid traveling crab, and a driving sprocket, said chain running oversaid driving sprocket, wherein said free wheel clutch is assembled withsaid driving sprocket.
 3. The apparatus of claim 1 wherein saidplurality of lifting forks comprises a first plurality of lifting forksand including a second plurality of lifting forks, each of said firstand second plurality of lifting forks being directed towards saidconveyor for jointly lifting said plurality of bales, said conveyordisposed to transport said plurality of bales in a direction transverseto said plurality of lifting forks.
 4. The apparatus of claim 3including a first traveling crab for carrying said first plurality oflifting forks and a second traveling crab for carrying said secondplurality of lifting forks, first vertical guide means for guiding saidfirst traveling crab in a vertical direction, second vertical guidemeans for guiding said second traveling crab in a vertical direction, afirst chain for driving said first traveling crab, a second chain fordriving said second traveling crab, a first driving sprocket, said firstchain running over said first driving sprocket, and a second drivingsprocket, said second chain running over said second driving sprocket,wherein said free wheel clutch comprises a first free wheel clutchassembled with said first driving sprocket and said second free wheelclutch assembled with said second driving sprocket.
 5. The apparatus ofclaim 4 including a first motor for driving said first chain and asecond motor for driving said second chain, said first and second motorsbeing synchronous.